To analyze a protein of interest, it is necessary to develop reagents that can detect it. Furthermore, to investigate the role of a protein in rheumatic disease models, it is frequently desirable to use monoclonal antibodies (mAbs) or recombinant proteins that block the function of the protein in question. A Protein Core has been established and has been productive during the last funding period. The RDCC proposes to continue support of this facility to provide services through a 1) Hybridoma facility to produce new mAbs;and 2) Production and Purification facility to produce high quality purified mAbs or recombinant proteins of interest. New services are planned to enhance the facility. Thus, the facility will continue to provide investigators with large quantities of proteins that can be used to analyze their molecules in relationship to rheumatic disease models.